Computational DFT analysis and molecular modeling on imidazole derivatives used as corrosion inhibitors for aluminum in acidic media.

[Display omitted] • Corrosion inhibiting of imidazole derivatives on aluminum was theoretically analyzed. • Neutral species can chemisorb or physisorb on the Al(1 1 1) surface. • Protonated species can only physisorb on the surface. • Methyl group increase adsorption capacity of imidazole molecule. The corrosion inhibiting effect of imidazole derivatives on aluminum was studied using density functional theory (DFT) calculations to assess the relationship between molecular structures and their corresponding efficiencies. The chemical reactivity of the neutral and protonated species (IM, Me-IM, IMH⁺ and Me-IMH⁺) was investigated, and the impact of methyl group substitution on the adsorption ability onto Al(1 1 1) surface was examined. Results revealed that the neutral species can be absorbed onto Al(1 1 1) surface by forming covalent bond N–Al, implying chemisorption as the mechanism of adsorption. It was also established that, the IMH+ and Me-IMH⁺ can be adsorbed via the Cl⁻ anion, which was already firstly adsorbed onto the Al(1 1 1) surface. The DFT calculations align well with the experimental results, suggesting that introduction of a methyl group at the 2-position of the imidazole ring enhances the adsorption ability. [ABSTRACT FROM AUTHOR]